You can examine the contents of these tables to obtain information
about Performance Schema monitoring characteristics. If you have
the UPDATE privilege, you can
change Performance Schema operation by modifying setup tables to
affect how monitoring occurs. For additional details about these
tables, see Section 25.11.2, “Performance Schema Setup Tables”.

To see which event timers are selected, query the
setup_timers tables:

The NAME value indicates the type of instrument
to which the timer applies, and TIMER_NAME
indicates which timer applies to those instruments. The timer
applies to instruments where their name begins with a component
matching the NAME value.

To change the timer, update the NAME value. For
example, to use the NANOSECOND timer for the
wait timer:

If there are Performance Schema configuration changes that must be
made at runtime using SQL statements and you would like these
changes to take effect each time the server starts, put the
statements in a file and start the server with the
--init-file=file_name
option. This strategy can also be useful if you have multiple
monitoring configurations, each tailored to produce a different
kind of monitoring, such as casual server health monitoring,
incident investigation, application behavior troubleshooting, and
so forth. Put the statements for each monitoring configuration
into their own file and specify the appropriate file as the
--init-file argument when you start
the server.